The risk for developing colorectal cancer is increased after a diagnosis of prostate cancer.

The risk for developing colorectal cancer is increased after a diagnosis of prostate cancer, a study published in the journal Cancer has shown.1

Because there are limited data on the risk of colorectal cancer among prostate cancer survivors, researchers sought to conduct a rigorous assessment of the risk after controlling for confounding factors and competing risks.

For the study, researchers analyzed data from 14 164 men with prostate cancer diagnosed between 1987 and 2009 and 69 051 men without prostate cancer from Manitoba, Canada. Patients were followed to the date of diagnosis of another cancer, death, emigration, or when the study ended at the end of 2009.

Results showed that men with prostate cancer had an elevated risk for subsequent development of colorectal cancer (HR, 1.14; 95% CI: 1.02-1.27). Researchers found that the risk was highest for rectal cancer (HR, 1.36; 95% CI: 1.09-1.71).

The study also demonstrated that treating prostate cancer with radiation was associated with an increased risk for rectal cancer compared with those whose prostate cancer was not treated with radiation (HR, 2.06; 95% CI: 1.42-2.99).

The findings suggest that colorectal cancer screening should be considered following a diagnosis of prostate cancer, particularly for patients considering radiotherapy.